Semiconductor device manufacturing: process – Packaging or treatment of packaged semiconductor
Reexamination Certificate
2000-09-29
2002-03-05
Nelms, David (Department: 2818)
Semiconductor device manufacturing: process
Packaging or treatment of packaged semiconductor
Reexamination Certificate
active
06352880
ABSTRACT:
FIELD OF INVENTION
The present invention generally relates to a semiconductor device production method and a semiconductor device, and more particularly to a production method of a semiconductor device in which an adjustable circuit, having a circuit element with electric properties adjustable through a laser trimming, is formed on a semiconductor chip, and to the semiconductor device produced by the method of production.
BACKGROUND OF THE INVENTION
As disclosed in Japanese Laid-Open Utility Model Application No.6-13148, there is known a semiconductor device in which a semiconductor chip is packaged or molded with a transparent material.
FIG. 3
shows such a semiconductor device that is disclosed in the above-mentioned publication.
In the semiconductor device of
FIG. 3
, an IC (integrated circuit) chip is packaged or molded with a transparent plastic material. The wafer chip within the semiconductor device is visible from a corresponding portion
1
A for the transparent plastic material, and only the portion
1
A can penetrate a UV (ultraviolet) light. The remaining portions
5
A of the upper surface of the semiconductor device are coated, printed or vacuum-deposited with an opaque material so that the remaining portions are opaque to external light.
In the semiconductor device disclosed in the above publication, the IC chip packaged with the transparent plastic material is an EPROM (erasable programmable read-only memory) in which data of the integrated circuit (IC) on the semiconductor device is erasable by irradiating UV light externally to the IC through the transparent plastic portion.
Further, as disclosed in Japanese Laid-Open Patent Application No.5-94905, there is known a production method that produces a semiconductor device including an adjustable resistor formed on a semiconductor chip, the adjustable resistor having electric resistance adjustable through a laser trimming.
FIG. 4
shows such a production method that is disclosed in the above-mentioned publication.
As shown in
FIG. 4
, in the conventional production method, a semiconductor device
2
B on a substrate
1
B is coated with an opaque resin
5
B, and a resistor
3
B is separately formed on the substrate
1
B. After the coating is performed, a laser beam
6
B is irradiated to the resistor
3
B to cut part of the resistor
3
B so that the electric resistance of the resistor
3
B is adjusted through the laser trimming. It is possible for the conventional production method to adjust the resistance of the resistor
3
B without altering the adjustment resistance values of the semiconductor device
2
B that are already finalized.
In the conventional production method of
FIG. 4
, a tester
7
B is used to observe the resistance values of the semiconductor device
2
B before and after the laser trimming is performed. The opaque resin
5
B which fully covers the semiconductor device
2
B serves to inhibit the laser beam
6
B from influencing the resistance values of the semiconductor device
2
B.
In the IC chip requiring the laser trimming (or the semiconductor device of the above type), the adjustable circuit including a circuit element, such as a fuse or a wiring, is formed on the semiconductor chip, and the electric properties of the circuit element, such as voltage, current or frequency values, are adjustable through the laser trimming. Herein, the laser trimming means that the whole or a part of the circuit element be cut away by irradiation of a laser beam. However, it is possible to extend the meaning of the laser trimming to include connection or welding operations to establish a connection of the wiring by irradiation of a laser beam.
In the above-described semiconductor device, the laser trimming is normally performed with the semiconductor chip in the wafer condition, and thereafter the assembly process is performed so that the semiconductor device is packaged.
More specifically, when the delivery of the products or samples of the semiconductor device of the above type to the customer is needed, it is necessary to perform the laser trimming with the semiconductor chip in the wafer condition, so that the electric properties of the adjustable circuit element in the semiconductor device, such as voltage, current or frequency values, are adjusted by the laser trimming so as to be in conformity with the customer's demanded values. Hereinafter, the needed laser trimming operation is called the user customizing operation.
When performing the user customizing operation, the laser trimming is performed with the semiconductor chip in the wafer condition to meet the customer demands, and thereafter the assembly process is performed so that the semiconductor chip is packaged. Finally, the final test is conducted, and the products or samples of the semiconductor device, passing the final test, are delivered to the customer.
In the assembly process, the semiconductor chip is cut off from the wafer, and the semiconductor chip is mounted on the tab. After the mounting is performed, the wire bonding is performed between the semiconductor chip, mounted on the tab, and the lead frame. After the wire bonding is performed, the semiconductor chip, connected to the lead frame by the wires, is packaged with the resin or molding material. Hereinafter, the assembly process will be considered as the assembly process including these steps.
In the final test, it is determined whether the semiconductor chip that is packaged with the resin material at the end of the assembly process meets the customer demands. Then, the products or samples of the semiconductor device passing the final test are delivered to the customer.
However, in the semiconductor device of
FIG. 3
, the data of the integrated circuit on the EP-ROM is erasable by irradiating UV light externally to the IC through the transparent plastic portion
1
A. Hence, the UV light used in the semiconductor device of
FIG. 3
is quite different from the laser beam used in the semiconductor device in which the adjustable circuit having the circuit element with electric properties adjustable through the laser trimming is formed on the semiconductor chip.
Further, in the semiconductor device production method of
FIG. 4
, the opaque resin
5
B which fully covers the semiconductor device
2
B serves to inhibit the laser beam
6
B from influencing the resistance values of the semiconductor device
2
B. It is impossible to adjust the resistance values of the semiconductor device
2
B by irradiating the laser beam to the semiconductor device
2
B through the opaque resin
5
B. There is a problem in that it is difficult for the production method of
FIG. 4
to perform the laser trimming for adjusting the electric properties of the circuit elements in the semiconductor device
2
B that is fully covered with the opaque resin
5
B.
As described above, in a conventional production method, when performing the user customizing operation, the laser trimming is performed with the semiconductor chip in the wafer condition to meet the customer demands, the assembly process is subsequently performed so that the semiconductor chip is packaged, and finally, the final test is conducted so that the products or samples of the semiconductor device, passing the final test, are delivered to the customer. Normally, when the conventional production method is used, it takes one through three months from the receiving of the customer's order to the delivery of the products or samples to the customer. The above conventional production method is difficult to provide speedy delivery of the products or samples to the customer in response to the customer's order. Further, it is difficult to obtain the customer satisfaction with the conventional production method.
A conceivable method for shortening the period from the receiving of the customer's order to the delivery of the products or samples to the customer is to always prepare a large stock for each of the samples of the semiconductor device that are expected to respectively meet various kinds of the customer demands. However, the cost
Matsuki Tatsuya
Nakamura Akira
Takai Masami
Takeda Satoshi
Cooper & Dunham LLP
Hoang Quoc
Nelms David
Ricoh & Company, Ltd.
LandOfFree
Semiconductor device and manufacture thereof does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Semiconductor device and manufacture thereof, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Semiconductor device and manufacture thereof will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2850081